The present invention relates generally to the field of data communication. More particularity, the present invention concerns a generic design methodology of a new family of Complementary Metal Oxide Semiconductor (CMOS) Integrated Circuits (IC) that is capable of moving data up to a speed of 10 Gbit/Sec when implemented on Silicon with a standard 0.18 xcexcm wafer process. Thus, its direct applications include a variety of subsystem and system functions such as Master Slave D-type Flip Flop (MS-DFF), Divider, Bang Bang Phase Detector (BBPD), Frequency Detection (FD), Phase and Frequency Detection (PFD), Voltage Controlled Oscillator (VCO) and Phase Locked Loop (PLL) in an optical switch IC for data communication.
Optical Fiber has been used in voice and data communication for some time now due to its high bandwidth and excellent signal quality resulting from its immunity to electromagnetic interference. The inherent optical data rate from a modulated single-mode laser beam travelling through an optical fiber is expected to well exceed 1000 Gbit/sec.
However, short of a completely optical communication system, the practically realizable bandwidth of fiber optical communication systems has been limited by the need of signal conversion between optical and electrical domain and the associated electronics hardware. Meanwhile, the usage of CMOS ICs has reached maturity in the electronics industry due to their advantage of low manufacturing cost, low operating power consumption, low supply voltage requirement while providing moderate speed in digital switching applications and fairly good circuit density. Because of these advantages, the fiber optical communication industry has been attempting to use the CMOS technology as the preferred electronics hardware base to act as a switch for the optical signal as well. Unfortunately, due to the traditional speed limitation inherent in CMOS switches, previous attempts have been unsuccessful in creating an optical switch with a data rate of 10 Gbit/sec.
In addition, past attempts in identifying a modified CMOS wafer process to achieve the same goal have resulted in poor functional characteristics such as excessive signal ripple, poor waveform jittering and the tendency of the operating IC to overheat quickly. For instance, the article xe2x80x9cA 10-Gb/s CMOS Clock and Data Recovery Circuit with a Half-Rate Linear Phase Detectorxe2x80x9d by Savoj and Razavi, published in IEEE Journal of Solid State Circuits, VOL. 36, NO. 5, May 2001, cited the possibility of creating a large ripple on the control line of the oscillator and hence high jitter in a BBPD of the oscillator and hence high jitter in a BBPD around such a high data rate. Other technologies have been tried as well, with various degrees of success, in an attempt to achieve the desired speed. These include using materials other than pure Silicon such as Silicon Germanium (SiGe), Gallium Arsenide (GaAs), Indium Phosphide (InP) or using a hybrid device architecture for the IC such as the combination of Bipolar and CMOS (BiCMOS), etc. Unfortunately these technologies all suffer from the same major drawback of requiring much higher manufacturing cost in terms of either high raw materials cost or high wafer processing cost with associated low yield.
The problem of high manufacturing cost is crucial, as it tends to discourage or otherwise delay the deployment and use of these components, which in turn directly affects the growth and potential of the optical networking market. A direct impact to the consumer community is, due to this speed bottleneck, the failure to provide for the proper broadband requirement necessary for the delivery of web video and interactive TV in a multimedia environment. Thus, such inherent desire for broadband communication of the consumer community can only be met by realizing a xe2x80x9clow costxe2x80x9d optical network for multimedia communication wherein an optical switch can be designed and made using standard, high volume, and low cost IC manufacturing processes.
The present invention is directed to a new family of CMOS IC and a generic design methodology of designing this new family of CMOS IC that is capable of moving data up to a speed of 10 Gbit/Sec when implemented on Silicon with a standard 0.25 xcexcm wafer process.
The first objective of this invention is to achieve a generic design methodology for a family of CMOS IC with a reduced amount of signal ripple after the respective logic signal levels are reached following a switching operation.
Other objectives, together with the foregoing are attained in the exercise of the invention in the following description and resulting in the embodiment illustrated in the accompanying drawings.